Variable pitch pulley



Aug. 10, 1943. P. F. KOCH VARIABLE PITCH PULLEY Filed March 5, 1943 Patented Aug. 10, 1943 1 2,326,468 VARIABLE PITCH PULLEY' Paul F. Koch, Oak Park, 111., assignor to Chicago. Die Casting Manufacturing Company, a corpo ration of Illinois it 'Apmicafim March 5, we, eam. 478,055,; '7'Claims. (C1 74 230 17) Y- The present invention relates to pulleys in which the pitch may be automatically varied upon changing the tension of the belt. It has for its object to produce a simple and novel conpulley shall be capable of expanding. In:v the arrangement shown; the slot 9 inthe inner hub extend entirely through the. wall of the latter.

and terminate short of the outer end of the hub,

struction which shall .consist' of a few sturdy whereas the slots. min the .outerhubare' in the parts, be efiective and reliable inoperation and form of grooves which leave the cylindrical exhave an indefinite life. terior surface'of the hub unbroken The various features'of novelty whereby my Loosely arranged within thehubi is aspider invention is characterized will hereinafter be comprising a'thick washer H provided atitspepointed out with particularity in the claims; but, riphery with radial arms .or. projections correfor a full understanding of my. invention and of sponding in number and in disposition to' the its objects and advantages, reference may be had slots or grooves in one or" the hubs. In the arto the following detailed description taken in rangement shown, there are four of such" arms, connection with the a compa yi raw placed ninetydegrees apart from eachother. wherein: 15. Two of the arms |2, disposed on the same diam- Figure 1 is a central longitudinal section of a eter, are flat on one sidezand rounded on-the pulley constructed in accordance with a preother side,-'whereas the other two arms, l3; are ferred'form of my invention; Fig. .2. is a section rounded on both .sides to form journals, as it on line 2-2 of Fig. 1; Fig. 3 isa, section on line were, about which the spider can be swung when 3-3 of Fig; 1; Fig. 4 is-asection-on line 4-1-4 of placing it in'position or removing it. .The' parts Fig. 1, showing: onlywhat appears. in'the plane are so proportioned that the spider may be inon which the sectionzis' taken; :and Fig. 7 5 is serted edgewise into the hub-assembly, be shifta perspective view of the spider which serves; as ed to enter thearms I3 in an opposite pair .of

. aspring follower and .to lock thetwo .pulleysec- Y registering slotsyand thespider be then swung tions againstrelative"rotary movements while about the axis of; these arms-until th arms.

' permitting re t ve axial movements. 15 9 enter the two remaining pairs of slots. 7

Referr n tot e drawin I nd 2. epresent Arranged axially of the hub '5 is'ga sturdy post complementary frustoconical. pulley sections s'o [4 having. a -th n n mp.

' p d as to p de b w t a groove o catedat is, which is screwed'i'nto and through va eyv-s ped in cross sectione a es the wall or weblithat separates the-boresaof these sections or pulley flanges-at thesmal-ler t hubs '5 n 5 om t g d of. ends of the cones, are slotted'radially.toprovide the post is s s av ahkerffn; valleys 3 separated by ribs or webs 4.}. .'Ihe.ribs; that. the p a be u r w by inserting a V or weos on one flange are adapted to enter the L SQreW driver through the hubs; The p is o; m the -L Thus-i when Se?- vided with an external shouldriin the form ofa tions or flanges are interengaged, as .in :Fig. 1, c01131. [3 near screw thrreaded portion; e thev belt-receiving valley is narrow and extends collar being small enough iniidiameterr. tdb able O.n1y Short distance g h to pass freely through the central hole in the npher'y AS d anges 9 40 spider; A second shoulder 19 is arranged on the. ig" the i; fi f vf post near'the free end of the latter; In the arg f g lonc gfi iggi g: 3g g rangement shown, this shoulder is a washer held 7 in'place by a cotter pin ,20. There isalso on the whereason .the other side is a short hub 6,1nto p which a shaft to support the pulley may extend. q Washer large? than, the p i t The hubfi is also in the form of a sleeve andmay Spider so that engages W he o t be provided with an internal longitudinal keysplder sumundmg t m -f surroundmg way I. These two hubs are, of course, coaxial post n the Washer 3 9 Y .relatively to each other and ltothe pulley. flange. 1s m f fi l s sprmg, h 9 5 Wh Thevmember-l is provided .with along hub in f i rom b h nd t a h theform'oi asleeve B-Which-surrounds and is. a T i y eio spring v de i slidableiit on the hub 5.;=-The hub 8preferably l i l'm pres r out the range of close extends somewhat beyond the free end of: the ing movements than 'does'an ordinary coil spring. Y hub 5. The hubs Sand Gare provided with regis- I It willib fi i e post; with its spr naicrmstering longitudinal slots at least; as long as the aunit complete in itseIL'theparts of. which' 'm'ay distance through which it isdesiredthat ,the:

-;be. assembled} ina factory, soithat the post .need

,-or in the gripping :pressure thereon, when only be screwed into the pulley wall in making the final pulley assembly. 7

It will be seen that the spring, through the washer 2|, constantly tends to force the spider toward the left as viewed in Fig. l. The arms [2 and I3 engage with the shoulders 23 at the inner ends of the slots or grooves It in the outer hub so that, when free to do so, this hub and the flange 2 ar'el'yi'eldingly held atthe left hand end of their range of movement. However, when the sides of the valley in the periphery of the pulley are subjected to forces tending to spread them apart, the flange member 2 is driven toward the right and, carrying thespider with it, compresses the spring. On account of, the shape of the spring, its resistance to compression, throughout the rangethrough which it need be Compressed in service, does not vary enough to subjectthe belt to an objectionable sidewise pressure, regardless of the radial distance of the belt from the axis the pulley;

The outer'end of th e hub B'may'be closed by 'means'of a'dome-like cap 24, frictionally"held-in @pla'ce; Thisipermits the use-of along post and spring, without'making the hub'unduly long.

It will further be'seen that, aside from the spring, thetwo washers and thecotterpin, there are' only four .parts to myiir'nprovedrpulley. All -0fthese parts are simple and sturdy and will -last indefinitely. Also, becausethe spring 'is as *sembledon theipost toformaself contained unit that need only be screwed intothe pulley in'as- .sembling :the latter *at the :place of manufacture, this can "be taken out and replaced when necessary, withoutdanger of losing any of its parts=or-disturbing their relation to each other. The cop over :the open end of thecom'positehub 'may besuch'a 'tight'fit 'that no usersis' likely'to :try-and take it oii. unnecessarily. However, should occasion arise to take the pulley apart,:the

userneed onlydetach it'from its supporting shaft "and, by unscrewing theapo theiend of the hub.

:Also, because the a spring st, ipus'h' the' capsoff from expanding under the pull of a.-belt, while in 1use,=the belt need only-be lengthenedor shortened without material increase in .the' tension: thereof the pitchdiameter is to be changed. p V While I haveillustratedand describedwith particularity only a single preierrediorm of my in fvention, I do not desire to; belirnited'tothe exact structural details thus illustratedand described; but intend to cover i all forms and arrangements 3 whichcome withinthe definitions or my invention constituting the appended claims.

Icla 'm: I 1. A jpulley compri'sing,'two complementary jfi'arige sections, "the ,fifst 'se'ction "having a long hblldwhub'on one side, the second "section surrounding the innerend of the hub and having a 'sreeve fitting "slidathly 'dvlfth'atfpallt 'of' thLhLlb prd'jecting'beyond said second sectionfaj post arranged axially of the hub and fixedatits n er end to the first flangefsiectiom,thepost having -thereon an "external shoulder etiitsouter end,

. the hub and i the sleeve having long registering longituiiinafl. slets therein, a loose; spider surrounding-said post and having armsprojecting'' through said slots and into 'sa idg'rbovesfland a sprang -d'evice' surrounding s'a'id p ost and' engaged its ends with said shoiildenand sald spider respectively.

,, c3. 3A 'ipull'ey cornp 7 ng two conipiementar'y :need' 'not at any time beestronger than :necessary to keep the pulley;

flange sections, the first section having a lon hollow hub on one side, the second section surrounding the inner end of the hub and having a sleeve fitting slidably over that part of the hub projecting beyond said second section, a post arranged axially of the hub and fixed at its inner end to the first flange section, the post having thereon an external shoulder at its outer end, the hub having longitudinal jslots through the wall 10 thereof, said sleeve having internal grooves registering with said slots, a loose'spider surrounding said post andhaving arms'projecting through said slotsiand into said grooves, and a spring device surrounding said post and engaged at its '15 ends with saidshoulder and said spider, respectively. j r

3. A pulley comprising two complementary flangehectionsjthe first section having a long hollow hub on one side, the second section surrounding'the inner end of the hub and having a sleeve-fitting slidably'overthatipart'oi the hub ;-projectingibeyondsaid-second section-a post arranged axially ofvthe'hub'and fixed at itsinner end to the firstxfiange section, theipost having thereon-an external shoulder at its outer-end, the hub having longitudinal slots-throughithe wall thereof, said sleeve having'iriternalzgrooves registering with said slots, a loose spider surrounding saidpost andhavingarmsmrojectingthrough said slots and into said ;grooves, a spring device surrounding said post and :engaged at its ends with said shoulder and said spider, respectively, -and -.a cap closin'g the outer end of said "sleeve.

4. A pulley comprising two complementary "flange sections, the, first section havingia long hollow hub' on the-inner side, these'cond section surroundingthe .innerend o'f the hub and 'havin a sleeve fitting sli'da'bly over .that'part-of the hub 40 projecting beyond said :second sectioh,"a.-post arranged axially of. the hub and :screwed at 1 its "inner end into i and through the first flange sec- ;tion, the :posthavingan external shoulder at its outer end, the -hub ha-vlng longitudinal slots ythrough thexwall thereof, said sleeve having internal grooves-registering with said slots,"a loose :spider surrounding said post and having a'rms :projecting through fsaidlslots and :into said rooves, and a spring device surroundingi s'aid post a'nd engagediat its ends with said shoulder vand 'said spider-respectively; anda second, sleev like hub on the outer side'of the-first flange sec- :tion coaxial with the first'hub and'adaptedito be :fittedupon'the-endiofa shaft. -5. A pulley comprising- -'two complementary .flange sections, thefirst section having a "long hollow hub ontheinnerside' the ssecondsection -surrounding the inner end oif the hub and having a'sleeve fittingislidably. overithat part of thehub projecting beyond said second section, a post arranged axialiyaof the hub andscrewed'a't its inner end'into and' through the firstflange section, the post having an external shoulder 'at its r-outersend and i a kerf in the 'e'rid'face at the oppo- 'site.1':end, :the ihub-.having longitudinal 'slots through the'wall thereof, said sleeve having insternal grooves registeringwithsai'd s'lots, -a 'loose spider surroundingzsaidlposti and having arm's projectin'g thrbugh said? ots and irito'saidfgrooves,

engagedmt it's ends withsaid 'shoulder and said sp'ider, respecti-vely; andaseconti, sleeve like hub -'o'n the outer-side'of the first-{fiange seotion coaxial with the first hub and adapted to -befitted upon "75 the end of a naft.

*and :a :spring d'evic'e s'urroun'di-ng "saidpost and:

6. A pulley comprising two complementary flange sections, the first section having a long hollow hub on one side, the second section sur- 7 rounding the inner end of the hub and having a sleeve fitting slidably over that part of the hub projecting beyond said second section, a post;

arranged axially of the hub and fixed at its inner end to the first flange section, the post having thereon an external shoulder at its outer end, the hub having longitudinal slots through the wall thereof, said sleeve having internal grooves registering with said slots, a loose spider su-rrounding said post and having arms projecting through said slots and into said grooves, and a hollow hub on one side, the second section sur-i rounding the inner end of the hub and havinga sleeve fitting slidably over that part of the hub projecting beyond said second section, a post ar ranged axially of-the hub and screwed at its I inner end into the first fiangesectien, the post having thereon an external shoulder at its inner end, the hubjhaving longitudinal slot through the wall thereof, said sleeve having internal grooves registering with "said slots, a loose spider surrounding the inner end of said post and hav-..

ing'arms projecting through said slots and into" said grooves, said spider containing a central opening large enough to permit the spider to be 1 moved along the post past the'said shoulder, a nut on the free end of the post a'washer on the post larger than the hole in and positioned outwardly from the spidenand a compression spring device surrounding said post and engaged at its ends with said shoulder and said washer, respec '20 tively.

PAUL F. KOCH; 

